How Your Pool Volume is Calculated
Determining your pool's accurate water volume is the foundational step to maintaining perfect water hygiene. Precise volume is necessary for calculating dosage sizes of chlorine, algicides, shock, and pool stabilizers. It also helps in buying the correctly sized pool pump and filter. This free Pool Gallon Calculator uses standard geometric calculations to deliver high-precision results for rectangular, circular, oval, and freeform pools.
Do you want to run construction estimations or measure specific materials? Discover our helpful tools in the Construction Calculator list to save you manual layout time.
Standard Mathematical Formulas Used
Volume formulas rely on multiplying your pool's surface area by its average depth, and applying multipliers to scale for distinct pool shapes:
- Rectangular Pools: Length × Width × Average Depth × Gallon Multiplier (7.48 for Imperial)
- Circular / Round Pools: π × Radius² × Average Depth × Gallon Multiplier (7.48 for Imperial)
- Oval Pools: π × (Length × 0.5) × (Width × 0.5) × Average Depth × 7.48
- Freeform / Kidney Pools: Average Length × Average Width × Average Depth × Shape Factor Coefficient (approx 0.85) × 7.48
How to Measure Average Depth
If your pool has a continuously sloping bottom from deep to shallow ends, you must find the Average Depth:
Average Depth = (Shallow End Depth + Deep End Depth) / 2
If your pool layout is constant (the same depth throughout the entire area), then the Shallow End Depth is equal to your Average Depth.